In this example we will have a look on how we can solve a multiphysics problem in NGSolve and the NGSPy interface. Therefore, we will consider a fluid-structure interaction problem, where the Navier-Stokes equations for the fluid part

$$\rho\frac{\partial u}{\partial t}+\rho(u\cdot\nabla)u-\rho\nu\Delta u+\nabla p = f$$ $$\text{div}(u) = 0$$

and the elastic wave equation for the elastic part